Float



Feb. 11, 1947. P. DUNSHEATH y 2,415,487-

FILOA'I- Filed Nm?.4 26. 1943 4 8,4 a F/G./.

lF/Gff. 29 2a 2e 27- 25 flug 21u veZt/or By# @M A ttorneys Patented Feb.11, 1947 FLOAT Percy Dunsheath, Abinger, England, assigner to W. T.Henleys Telegraph Works Company Limited, Westcott, Dorking, England, aBritish Company Application November 26, 1943, Serial-No. 511,847 InGreat Britain November 23', 1942 7 Claims.

This invention relates to long flexible floats for use in themanufacture of water-buoyant electric cable or for other purposes. Insuch cable the long flexible float generally forms a core about whichare disposed one or more layers of wires constituting the cableconductor, which is usually provided with a flexible waterproofcovering. For some purposes it is essential that the cable shouldpossess a high resistance to compression in a laterall direction and yetbe flexible lengthwise to permit of frequent reeling and unreelingwithout damage. These requirements necessitate a core that is rigid in alateral direction but locally compressible in a longitudinal driection.obtained by making the core in part of resilient material, generallysoft rubber, and in part of relatively rigid material, for instance,ebonite, wood or metal. By the present invention we' provide analternative form of flexible float in which the need for rubber or likeresilient material is very much reduced or entirely avoided. It is builtup of a series of hollow cylindrical bodies each having circumferentialwalls of metal, plywood or a tough plastic and a pair of end walls.These containers are disposed end to end and attached to one anotheralong the axis of the float, that is, at points lying on or in theregion of the axis. A clearance'is provided between the radially outerparts of the end walls of each two succesive containers, and one (orboth) of the two contiguous end walls thereof is of thin metal andsufllciently flexible to permit the containers to take up positions withtheir axes inclined to one another.

The invention will be further described with the aid of the accompanyingdrawing, wherein- Figure 1 shows, principally in elevation, a portion ofa long length of a preferred formi of flexible float constructed inaccordance with the invention,

Figure 2 shows, partly in elevation and partly in section, a series ofhollow containers with thin metal end walls connected together inVarious ways to form a portion of a further length of flexible floatconstructed according to the invention,

Figure'3 shows, partly in elevation and partly in section and on thesame'scale as Figure 2, a

further series of hollow containers connected together in various otherways to form, in accordance with the invention, a portion'of a yetanother length of flexible float constructed accordins to the invention,and

Figure 4 is an elevation of `alength'of buoyant Hitherto localcompressibility has been cable embodying a flexible float of the formshown in Figure 1.

Referring first of all more particularly to Figure l of the drawingy itwill be seen that the flexible float isV made up of a number ofcylindrical containers I disposed end to end in axial alignment. Thepreferred material for these containers is tin-plate but other metalsmay be used, for instance, lacquered sheet iron or steel, sheet brass orsheet aluminum or, as indicated above, the circumferential walls 2 maybe ofplywood or a tough plastic instead of metal. Each container l isattached to the next container along the axis of the float either at apoint 3 on the axis or at a number of such points clustered around theaxis. The clearance 4 is provided between the radially outer ports ofthe end walls 5 and 6 of each two succesive containers by making thecentral part of at least one of them roject outwardly beyond theradially outer part, for instance, by making it convex outwards eitherin the form of a flat cone as shown at 6 in Figure 1, or in the form ofa shallow dome as shown in Figure 2. Of the two contiguous end walls ofeach container, one of them, 5, is of thin metal and sufficientlyflexible to permit the twocontainers to take up a position in whichtheir axes are inclined to one another. The other may or may not beflexible. For most purposes adequate lateral rigidity of the float andsuflicient longitudinal flexibility will be obtained if the flexible endwall 5 is of the same thickness as the circumferential wall 2, but insome cases it may be advantageous to make it of thinner metal. As a flatend wall is more flexible than a conical or domed end wall, We prefer tomake one end wall of each container flat and the other conica1 and toattach the flat end of one container to the conical end of the next, asshown in Figure 1, thereby obtaining adequate peripheral clearance and ahighly flexible float. One or both 0f the end Walls Iwhether flat or ofconvex form may be rendered more flexible by providing therein one ormore annular corrugations as shown at l to the right hand side of Figure1, but this will not generally be necessary. The end walls 5 and 6 andthe circumferential walls 2 may be made from separate parts and seamedtogether in any convenient manner as indicated at 8, for instance, inthe case of containers made wholly of metal, by folding and soldering orfolding and welding or folding and cementing. Alternatively, thecircumferential wall and one end wall may be ntegral, being formed byadrawing, pressingor spinning operation, and the container completed bythe addition of a second end wall, or the container may be formed of apair of cupped members by seaming'the rim of one to that of the other.These two forms present the advantage that only one circumferentiallyextending seam is required.

The necessary clearance between the radially outer parts of adjacentcontainers may be obtained in one or more of several ways. As indicatedabove, the entire surface of one or of both of the end walls may havethe form of a shallow cone with a flattened apex, or the entire surfaceof the end walls may be in the form of a shallow dome. Containers withend walls of the latter form are shown in Figure 2. Alternatively, bothend walls of a centrally attached pair may be flat and held in spacedrelationship by the means attaching them together.

The means for connecting together successive containers may varyaccording to the shapes of the end walls and whether only one or bothare of metal. Where both are of metal and the clearance is provided bythe central part of one or both of them projecting endwise beyond theradially outer part, they may be secured by soldering them together overa small area near the centre or by spot welding them at the centre, theformer being preferable for containers of tinplate. Alternatively, theymay be connected as shown on the extreme left of Figure 2, by providinga small hole in the centre of each wall and forcing a re-entrant edge 9of one hole through the other and turning it over by a tool andsoldering, the edge of the other hole preferably being bent over asshown at I0, or they may be bolted or riveted together by a solid rivetIl or a hollow rivetv I2. In the case where both end walls are flat, adistance piece I3 may be inserted between them, in the form of a shorttube I3, through which passes the securing rivet I4, as

shown on the extreme right of Figure 2. All these securing means yetdescribed result in a' rigid attachment of the central part of one endwall to the central part of the next. This rigid attachment does not,however, result in a rigid string of containers, for the walls, whilstbeing sufficiently strong in tension to maintain the cylindrical` shapeof the end part of the circumferential wall under normal Workingconditions, are laterally flexible and deform easily to the slightextent necessary to permit the float to bend to a reasonable curvature,the action being, in the case of a pair of curved walls in the nature ofa squeezing together resulting in an increase in the length of the lineof contact bei tween them rather than a change in location of the pointof contact, as occurs in a true rolling action'.

In place of a rigid attachment, successive containers may be connectedtogether by a short flexible rod, for instance, as indicated on theextreme left of Figure 3, by a short rod I5 of tough rubber havingcircumferential grooves I6 near each end, the diameter at the bottom ofthe grooves corresponding with the diameter of a central hole in eachend wall 5 and 6 and the ends of the rod being rounded off so that theycan be pushed through the holes to bring the edges thereof intoengagement with the walls of the grooves. Instead of a flexible rod ashort length of flat metal strip may be employed. Such a strip I1 isshown in Figure 3 between the second and third containers from the left.It may be secured by soldering as shown at I8 or by welding'. Where suchconnections are used, successivestrips in the series are preferablydisposed so that they lie in planes at right angles to another. As shownin Figure 3, the flat strip I1 connecting the third to the fourthcontainer from the left lies at right angles to that connecting thesecond to the third. The purpose of this arrangement is to distributethe additional flexibility imparted by the strips so that the float issubstantially uniformly ilexible in all directions. Alternatively, aconnector of the form shown in Figure 3 between the fourth and fifth,and fifth and sixth containers from the left may be used. This comprisesa folded metal strip I9 comprising three overlying portions, the middleand one outer of which are united by a folded edge 20 and the middle andthe other outer of which are united by a second folded edge 2I extendingat a large angle, preferably a right angle, to the first edge. Thefolded strips I9 are attached to the end walls by soldering, successivestrips lying at a large angle preferably an angle of to each other, asis clearly shown in Figure 3, with the object of ensuring that the oatis, as far as practicable, uniformly flexible in all directions.

`It will be appreciated that in most cases it will be necessary toattach the end walls of successive containers together before one of thecontainers is completed. In certain cases it may be preferable tocomplete the attachment of each two contiguous end walls before eitherofthe two containers of which they will form part are complete so thatthere is access to both sides of the attachment. Where the method ofattachment involves an aperture in the end walls, as, for instance, inthe methods shown in Figure 2, it is advisable to seal this wherepossible to prevent continuous flooding of the whole string ofcontainers. Where the ends are riveted by solid rivets, this may beeffected by means of a gasket 22 between the two walls 5 and 6 which isa close fit on the rivet II, or by soldering or lacquering over therivet on the inside surfaces of the walls as shown at 23. Where hollowrivets or eyelets are used the aperture may be plugged either in everycase or at intervals along the length of the core or another form ofattachment, for instance, soldering or a solid rivet may be employed atsuch intervals.

The containers may be filled with gas under pressure. This will serve todetect leaks present in the containers before the application of aconductorto the core and those which may arise subsequently when thecable is in service. The gas may be introduced through an appropriateaperture in the container wall which is thereafter sealed off or begenerated in situ in the container by the introduction of gas-producingpellets 24. In some instances the gas may also serve to produce thedesired bulging of the end walls of the container.

When the improved float is to form a core for a buoyant electric cable,it is especially desirable to keep the diameter a minimum. To this endthe walls of the containers will be as thin as is compatible with theneed to provide adequate support for the conductor both during themanufacture of the cable and subsequently. Forinstance, with a heavycurrent cable requiring a buoyant core of about three inches diameter wefind that it will generally be satisfactory to construct the containersof tin-plate having a thickness of between ten mils and fourteenmils andto make the clearance between the circumferential portions of each pairof contiguous end walls approximately one quarter of an inch. Such acore may be bent round a drum of 36 inches diameter without becomingdamaged. In the example of buoyant cable shown in Figure 4, thethickness of the walls of the gas-filled containers I has necessarilybeen exaggerated. As will be seen, the conductor comprises an innerlayer 25 of wires laid up round the string of containers I and an outerlayer 26 of wires laid up in the opposite direction over a separatinglayer 21 of rubberproofedfabric tape. This outer layer is furnished witha wrapping 28 oi similar tape and the whole provided with a tough rubbersheath 29.

It will be appreciated that in many cases it will be advantageous to usefor the core of a buoyant cable or for other purposes, a float in whichall the containers are of identical form and coupled together in thesame way. However, it is by no means essential that this should be soand in some cases it may be advantageous to use one form of constructionof container and one form of attachment in one part of the core andanother form or forms in another part. For instance, parts of the floatthat are subjected to more severe flexing than others may be constructedof containers of which both end walls are flexible and of one or more ofthe forms of coupling members described with reference to Figure 3 ofthe drawing, whilst the remaining parts of the float may i comprise oneor more of the forms described with reference to Figure 1 and Figure 2of the draw- 111g.

What I claim as my invention is:

1. A long flexible float comprising a number of hollow cylindricalcontainers, each having a pair of end walls and an inflexiblecircumferential wall, disposed end to end with a clearance between theradially outer parts of each two successive containers, and meansconnecting together along the axis of the float the contiguous end wallsof each two succesive containers, at least one of the two contiguous endwalls of each two successive containers being of thin metal and flexiblewhereby to permit the containers to take up positions with theirrespective axes inclined to one another.

2. A long flexible float comprising a number of hollow cylindricalcontainers disposed end to end and each having a pair of end walls andan inflexible circumferential wall, and means for attaching saidcontainers to one another along the axis of the float, at least one ofthe two contiguous end Walls of each two successive containers having a.central part projecting beyond the radially outer parts and at least oneof the two contiguous end walls being of thin metal and flexible,whereby to allow the attached containers to take up positions with theirrespective axes inclined to one another,

3. A long flexible oat comprising a number of hollow cylindricalcontainers disposed end to end and each having a pair of flat end Wallsand an inflexible circumferential wall, and means connecting togetheralong the axis of the float the contiguous end walls of each twosuccessive containers and holding the said successive containers inspaced relationship to one another, at least one of each pair ofcontiguous end walls of said containers being of thin metal and flexiblewhereby to permit the containers to take up positions with their axesinclined to one another.

4. A long flexible float comprising a number of hollow cylindricalcontainers, each having a pair of end walls and an inflexiblecircumferential wall, disposed end to end with a clearance between theradially outer parts of each pair of contiguous end walls, means formaking an inflexible connection between the central parts of thecontiguous end walls of successive containers, at least one of each twomutually rigidly attached end walls being of thin metal and flexiblewhereby to permit the containers to take up positions with theirrespective axes inclined to one another.

5. A long flexible float comprising a number of hollow cylindricalcontainers, each having a pair of end walls and an inflexiblecircumferential wall, disposed end to end with a clearance between theradially outer parts of each pair of contiguous end walls, and a numberof discrete coupling members each of which is flexible in at least onedirection and is secured at its ends to the external surfaces of thecontiguous end walls of two successive containers whereby to couple saidcontainers together along the axis of the float and hold them in spacedrelationship to one another, at least one of the two contiguous endwalls of said containers being of thin metal and flexible.

6. A long flexible float comprising a number of closed metal canisterseach having one flexible end wall and one end wall in the form of asha1- low cone with a flattened apex, disposed end to end with the apexof the coned end wall of each container contiguous with, and solderedto, the central part of the flexible end wall of the next container.

7. A long flexible float comprising a number of closed metal canisters,each having a pair of flat end walls at least one of which is flexible,disposed end to end so that at least one end wall of each contiguouspair is a flexible wall, and a number of coupling members each of 'whichcouples together the central parts of a pair of contiguous end walls, isof metal strip and comprises three overlying portions, the middle andone outer of which are united by a folded edge and the middle and theother outer of which are united by a second folded edge extending at alarge angle, preferably a right angle, to the first edge, successivecoupling members lying at a large angle, preferably an angle of 180.

PERCY DUNSHEATH.

le of this patent:

UNITED STATES PATENTS Number Name Date 2,180,731 Dickinson Nov. 21, 1939411,161 Maynard Sept. 17, 1889 292,281 Brewster Jan. 22, 1884 1,403,362Walters Jan. 10, 1922 1,667,510 Coe Apr. 24, 1928 1,810,079 JennisonJune 16, 1931 1,843,452 Jennison Feb. 2, 1932 2,048,811 Peirce July 28,1936 FOREIGN PATENTS Number Country Date 312,464 British May 30, 1929

